The tank or the connection to the tank pump. The first thing I ever fixed on my SD was the washer tank. The plastic nipple at the bottom leading to the pump was cracked. I carefully drilled out the ID and epoxied in a brass tube (specifically a scrap piece of antenna mast). It's still holding almost 9 years later.

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.